This invention relates generally to the field of magnetic data storage devices, and more particularly, but not by way of limitation, to an improved E-block formed from stamped and drawn actuator arms, the E-block used to support one or more read/write heads adjacent a corresponding number of disc recording surfaces.
Disc drives are data handling systems used to provide primary data storage operations in modern computer systems and networks. A typical disc drive comprises a head-disc assembly (HDA) which houses mechanical portions of the drive, and a printed circuit board assembly (PCBA) mounted to an outer surface of the HDA which supports electronic circuitry used to control the HDA.
Typically, a HDA comprises a number of magnetic discs affixed to, and rotated by, a spindle motor at a constant high speed. An actuator supports an array of read/write heads adjacent the disc surfaces. The surface of each disc is a data recording surface divided into a series of generally concentric recording tracks radially spaced across a band having an inner diameter and an outer diameter. The data tracks extend around the surfaces of the discs and data are stored to the tracks by the heads in the form of magnetic flux transitions. Typically, each data track is divided into a number of data sectors that store fixed sized data blocks.
An actuator motor, such as a voice coil motor (VCM), rotates the actuator, and hence the heads, across the disc surfaces. The control circuitry on the PCBA includes a read/write channel which interfaces with the heads to transfer data between the tracks and a host computer, and a servo control system which drives the VCM to provide head positional control, based on servo data stored in servo fields interspersed among the data sectors and written during disc drive manufacturing.
Continued demand for disc drives with ever increasing levels of data storage capacity and data throughput have led disc drive manufacturers to seek ways to increase the storage capacity of each disc surface and improve operating efficiencies of the disc drive. Coupled with the continued demand for high-performance, high-capacity disc drives is the continued erosion in the price per megabyte of storage capacity disc drive manufacturers are able to receive from the market for their products. To remain viable, disc drive manufacturers are under continual pressure to reduce the cost per megabyte associated with the manufacture and marketing of their product offerings.
One area for opportunity is the actuator used within the disc drive. The industry has substantially settled on a design featuring a flat coil rotary actuator with a body portion rotatable about a bearing assembly and actuator arms which project from the body portion toward the discs. This portion of the actuator is sometimes referred to as an xe2x80x9cE-blockxe2x80x9d or xe2x80x9cactuator core.xe2x80x9d Typical methodologies for forming E-blocks have included casting or extruding a solid form with overall dimensions corresponding to the desired E-block volume followed with extensive secondary machining operations to form the actuator arms and the coil support arms; by stacking planar actuator arms with interleaved spacers and securing the assembly with threaded hardware; and by forming planar actuator arms and overmolding with a suitable material to arrive at the final configuration.
While these and other prior art approaches have been found operable. demands to produce consistent and repeatable results, particularly from the performance contributions from the E-block, have increased the amount of time required to establish critical surfaces of the E-block, burdening the actuator with increased cost pressures. Thus, there remains a continued need for improved approaches to forming an actuator E-block with tightly controlled tolerances in a fast and cost efficient manner, and it is to such improvements that the present invention is directed.
The present invention is directed to an improved E-block used in a data handling system such as a disc drive to support one or more read/write heads adjacent a corresponding number of axially aligned recording surfaces.
In accordance with preferred embodiments, the E-block is formed by providing feed stock of a suitable material, such as aluminum, and orienting the feed stock along a planar orientation. A portion of the feed stock is drawn out of plane to form an extension portion. The feed stock is stamped (blanked, cut) to separate an actuator arm member having a substantially planar actuator arm from which the extension portion extends, the actuator arm configured to support at least one read/write head. The extension portion of the actuator arm member is affixed to a second member using a suitable process such as swaging or welding.
The second member preferably comprises a motor support member having a coil support arm configured to support an actuator coil of an actuator motor. The second member is also preferably stamped from the feed stock. The motor support member also preferably comprises an actuator arm, so that the extension portion of the actuator arm member nominally establishes the distance between the adjacent actuator arms so that the arms can be nested adjacent opposing sides of a recording disc.
The E-block can further be configured to comprise a second actuator arm member nominally identical to the first actuator arm member. The first and second actuator arms can be stacked together, or affixed to opposing sides of the motor support member to form the E-block. Suitable coining operations are performed to establish critical dimensions to ensure repeatability and reliability.